I've had a chance to use Mr. Yes several times, primarily because DAG never responded to my inquiries. I am not kidding. I 've called and emailed this person with requests for camera and lens work but he never bothered to reply. Sherry Krauter did reply to one of my requests for lens-repair (but many other inquires from the past went on unanswered) yet she wanted me to pay up-front so she can check the lens. It was not a small sum either and I found that to be odd so I asked Youxin for help. After describing the problem to him, he actually provided me with a solution and explained how I can fix it myself (it was an easy fix in the end). Mr. Ye, is very responsive, and even though he may be self-taught I wouldn't call him amateurish (as some describe him in the posts above). If he can't do it or doesn't know how to do it, he'll refer you elsewhere. So feel free to reach out to him and see how it goes.